Rinnai HE Series How To Use Manual page 166

unit will try to fire three times. That will not occur on the immediate code 12. The fan motor may try to
come on but immediately goes into a code.
The immediate code 12 or 19 is an indication of a short circuit within the appliance. Could be a short in a
wiring harness, water flow control or bypass valve or any other component within the DC circuit. One
way to track this down is to unplug one component at a time and try to cycle the unit on. If you unplug
any component and the unit cycles three times after unplugging it, the short is in that device.
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